Clamshell earth-moving machine



July 24, 1956 BEVAN 2,755,946

CLAMSHELL EARTH-MOVING MACHINE Filed Jan. 2, 1952 2 Sheets-Sheet l INVENTOR. JAMES 5E m/v y 4, 1956 .1. l. BEVAN CLAMSHELL EARTH-MOVING MACHINE 2 Sheets-Sheet 2 Filed Jan. 2, 1952 INVENTOR. JAM IE5 5E" VAN A/AS 4 0242,

nited States Patent CLAMSHELL EARTH-MOVING MACHINE James I. Bevan, East McKeesport, Pa. Application January 2, 1952, Serial No. 264,555

7 Claims. (Cl. 214147) This invention relates generally to earth-moving vehicles and more particularly to earth-moving vehicles employing a clamshell type of digging bucket.

A clamshell bucket is ordinarily supported by cable lines from the end of a boom and is dropped in an open position for the purpose of setting the teeth to dig into the earth and upon hoisting the hinge portion of the bucket the clamshell jaws close, biting into the dirt to dig the same.

The principal object of this invention is the provision of a clamshell bucket universally connected to the end of a dipper stick of a shovel or to the end of a hoe stick permitting the bucket to employ the force and Weight of the boom and the stick when digging owing to the fact that it is attached directly thereto. By eliminating the flexible connection, namely the cable suspension v of the clamshell bucket, one is enabled to employ the force and weight of the boom and the stick to slowly forcethis clamshell to dig into the dirt with greater effort than it would normally have when dropped in its open position and merely closed as it is presently operated.

Another object of this invention is the provisionof a swiveled joint between a clamshell bucket and the stick or boom on which the bucket is mounted, for the purpose of rotating. the clamshell bucket ona vertical axis so as to adjust the angular position of the bucket to permit one to dig in a line parallel with that of the travel of the machine Without being over the area that is being excavated such as along the side of a wall or building.

Another object of this invention is the provision of a clamshell digging mechanism wherein a positive force may be applied to an open clamshell, moving it into the material to be dug and wherein the device may be operated to control the force and thus the extent of the bite of the clamshell and in an angular'positio'n relative to the fixed location such as the wall or building.

Other objects and advantages appear hereinafter in the following description and claims.

The accompanying drawings show for the purpose of exemplification, without limiting the invention or claims thereto, certain practical embodiments of the invention wherein: a

Fig. l is aview in side elevation ofa clamshell bucket as applied to a backhoe mechanism.

Fig. 2 is a large detail. view showing. the universal joint between the clamshell bucket and the stick of a mechanically operated device.

Fig. 3 is a sectional view taken alongv line of Fig. 2.

Fig. 4 is a. sectional view takenalong line i -4: of Fig. 2.

Fig. 5 is a plan view showing the relative position. of the digging mechanism: and a clamshell bucket comprising invention.

Fig- 6' is a view on. side elevation showing, the clam shell bucket as applied to a shovel structure.

2,755,946 Fatented July 24, 1956 Fig. 7 is a large detail view of the swivel mechanism shown in Fig. 6.

Fig. 8 is a sectional view taken along the line 8-8 of Fig. 7.

Fig. 9 is a view in side elevation showing the clamshell as applied to a hydraulic backhoe type of digging machine.

The structure as shown in Figs. 1 to 5 is that of a backhoe type of an earth-moving vehicle which comprises the mobile frame as indicated at 1 provided with the endless tracks 2 with the centrally disposed rotating gear 3 and the circle track 4 for rotatably supporting the deck 5 of the machine which carries the operating mechanism housed in the cab 6, together with the operating station. The deck 5 has pivoted to the front end thereof, as indicated at 7, the boom 8 which is telescopically adjustable relative to the base 5. The boom hoist frame member 10 carries the pulleys 11 which function with the pulleys 12 pivotally supported on the upper end of the stick 13 which in turn is pivoted as at 14 to the end for the purpose of raising and lowering the boom. This type of mechanism is employed as the backhoe wherein the movably mounted stick 13 is pivotally supported on the end of the boom. When employed as a shovel a different type of stick is used as shown in Fig. 6.

The lower end of the stick 13 is provided with a universal joint member 15 as shown in Figs. 2 and 3. One pivot member of the universal joint is shown in Fig. 3 as a pair of aligned pin members 16 pivotally connecting the spaced tongues 17 on the end of the stick 13 to the intermediate bearing plate member or box menu ber 18. The other pivot member of the universal joint is disposed at right angles to the pins 16 and is illustrated by the pins 20 pivotally supporting the upwardly projecting arms 21 to the spaced tongues 22' on the lower end of the box member 18. The upwardly projecting arms 21 are rigidly connected with the bearing plate 23 which mates with the bearing plate 24. The plate 24 is pro vided with the downwardly extending gusset members 25 for pivotally supporting the pulleys 26 on the shafts 27 and is provided with the depending links or arms 28 which support the bucket members 39 that are pivotally hinged together as indicated at 31 in Fig. l. The plate 24 has a centrally disposed upwardly extending hollow shaft 32 which is threaded at its upper end to receive the nut 33 and is provided with the washer M for rotatably holding the plates 23' and 2a in assembled relation and the bucket as suspended therefrom. These swivel. joints may be provided with antifri'cti'on bearings. The plates 23 and 24 are provided with holes such as indicated at 35' and 36, which are not aligned with one another but one or more holes may be aligned by rotating one plate relative to the other, and when the bucket is positioned at the proper position at an angular rcia tion to the beam, the holes that are aligned receive t. e bolt 37 or pins for the purpose of maintaining: thisv alignment to permit the operator to dig at the same angle as illustrated in Fig. 5. When it. is desired to the alignment the bolt 37 is removed and the plate. 24 is again turned by hand. to the desired position at Wt -lr time another pair of aligned holesis. sought and. the bolt- 37 is: replaced. More than one bolt may be employedfor locking the two plates together and thereby take the total strain off the vertical shaft 32.

The operating cable for the clamshell. bucket 39 is in dicated at 40- and passes over the pulley 4i and over the pulley 42 at the: end of the beam. The cabie centi nue's down through the stick 13' and down through the spaced pin member 16- and isengaged by the rollers 43 fo r'm'ain taming. it in alignment in the center ot'theuniv'ers'ai jo t The second set of rollers. 44 is: provided. adjacent the' pivot' pins 20 for maintaining the alignmentof the cable 40.

The cable 40 then continues down through the center of the hollow shaft 32 and is looped around the pulley 45 on the pivot 31 of the bucket and passes upwardly and is attached to the pin 46 as indicated in Fig. 3. More than one pulley, such as indicated at 26 and 45, may be employed depending upon the mechanical advantage one desires to have for closing the clamshell buckets. If more than one pulley is provided the single line cable weaves between these in the manner of block and tackle and the free end is attached as indicated at 46.

The mechanism as shown in Figs. 1 to is a mechanical, line-operated clamshell bucket pivotally supported on the end of a stick that is fastened to the live boom of a backhoe type of machine. The clamshell bucket 30 may thus dig along the line parallel to the movement of the machine such as illustrated in Fig. 5 and still dig only a trench as Wide as the bucket. In addition to this advantage the weight of the boom and the stick may be placed on the bucket while digging to enable it to bite into more dirt than it would from its own weight. A trip line may be employed to release the bucket in an ordinary manner. Such a trip line is operated from the cab and releases the hoist line 40 so as to permit the center of the clamshell to drop to the position as shown in Fig. 1.

In the structure as shown in Figs. 6, 7 and 8 the clamshell bucket is supplied to a device wherein the boom 50 is of the shovel type and the dipper stick 51 is pivotally as well as reciprocally mounted on the boom to move in and out in a well-known manner through the saddle 52. The lines 53 are employed to raise and lower the boom thus making it a live boom and the extra lines 54 pass over the pulleys and the ends of the boom to raise and lower the end of the stick as in the manner of an ordinary shovel. However the dipper stick 51 is provided with a universal joint such as indicated at 55 having the upper swivel joints 56 and the lower swivel joints 57. The upper swivel joints which are shown in Fig. 8 support the universal member 60 from the end of the stick 51 and is provided with depending arms 61 which receive the pins 57 for pivotally supporting the swivel mechanism of the bucket thereto which comprises the plate members 23 and 24 as previously described. The plate 23 is provided with the upwardly projecting arms 21 which are pivoted at 57 to the universal joint structure and are spaced apart to receive the servomotor member 62. This servomotor is mounted relative to the arms 21 by being mounted in the spaced socket 63 and is capable of rotating the lower plate member 24 relative thereto. As shown the swivel member 64 is rotatably supported in the plate 23 and has a nonround socket connected to the nonround head of the rotary drive mechanism 65 of the servomotor 62. The member 64 has a downwardly projecting stem 66 which is secured in place by the nut 67 and is provided with a pin 68 that passes through the stem 66 and is connected to the gussets 25. Thus when the servomotor is actuated it turns the stem 66 through the pin 68 and the whole of the clamshell bucket is rotated.

A piston rod 70 is pivotally supported to the plates as indicated in Fig. 8, and it is arranged to operate in the doubleacting hydraulic cylinder 71 and is supported by the hinge mechanism 31 of the clamshell bucket member 30 to operate the same. As shown in Fig. 6 the piston is expanded and the clamshell bucket members are open and when the piston is hydraulically contracted into the cylinder 71 the clamshell bucket is closed. A hose line 72 is brought up from the cab to the bucket mechanism for operating the same.

The earth-moving vehicle structure may be somewhat different than either a backhoe or a shovel dipper and it may be applied to a tractor mechanism in any manner that any backhoe structure has been constructed. It is more readily adapted to a backhoe structure owing to the fact that the mechanism is pivotally supported on the very end of the beam, and such a beam may be operated by hydraulic jacks in place of lines.

Such a structure is disclosed in Fig. 9 wherein the body of the vehicle 74 has a turret 75 pivotally supported on its rear end from which the boom 76 is mounted. The outer end of the boom is provided with a pivot 77 on which the stick 78 is pivoted intermediate of its ends, the other end being universally and swivelly connected at 79 to the bucket 80 and the opposite end has pivoted thereto one end of the piston 81 that operates in the double-acting cylinder 82; the other end of which is pivotally secured to a bracket on the beam. A cylinder 83 with a piston 84 is pivotally secured to the swivel for the clamshell bucket for the purpose of operating the same. A cylinder 85 is pivotally secured to the upper end of the frame 87 and is pivotally attached to the beam 76 for the purpose of changing the angular position of the same to make it a live beam. These pistons are operated by controls similar to that of the samev type of mechanism having a backhoe. The beam and the stick are hydraulically actuated and the clamshell bucket itself is hydraulically opened and closed.

I claim:

l. A self-contained earth-moving machine comprising a base having a live boom mounted thereon, a bucket stick movably mounted on said boom, universal joint means providing pivots on two horizontal axes at right angles to each other mounted on the outer end of said bucket stick, a clamshell bucket suspended from said universal joint means to permit the bucket to hang vertically, a rotary adjustable swivel member interposed between said universal joint and the clamshell bucket to angularly position the clamshell bucket on its vertical axis relative to the boom and bucket stick, and control means operable from said base for actuating the boom and the stick and the bucket to operate them independently of each other.

2. A self-contained earth-moving machine comprising a base having a live boom mounted thereon, a bucket stick, a saddle on said boom to movably support the bucket stick thereon, means to run the bucket stick in and out of said saddle to change the eifective length of the same, universal joint means providing pivots on two horizontal axes at right angles to each other mounted on the outer end of said bucket stick, a clamshell bucket suspended from said universal joint means to permit the bucket to hang vertically, a rotary adjustable swivel member interposed between the said universal joint and the clamshell bucket to angularly position the clamshell bucket on its vertical axis relative to the boom and bucket stick, and control means operable from said base for actuating the boom and the stick and the bucket to operate them independently of each other.

3. A self-contained earth-moving machine comprising a base having a live boom mounted thereon, a bucket stick movably mounted on said boom, universal joint means providing pivots on two horizontal axes at right angles to each other mounted on the outer end of said bucket stick, means to shift said boom to change the relative position of the bucket stick from said base, a clamshell bucket suspended from said universal joint means to permit the bucket to hang vertically, a rotary adjustable swivel member interposed between the said universal joint and the clamshell bucket to angularly position the clamshell bucket on its vertical axis relative to the boom and bucket stick, and control means operable from said base for actuating the boom and the stick and the bucket to operate them independently of each other.

4. The structure of claim 1 characterized in that said rotary adjustable swivel member includes a pair of horizontally disposed plates pivotally attached to each other, each having a series of holes in opposed relation to each other, and a bolt positioned in aligned selected holes to fix the angularity of the bucket in a predetermined position.

5. The structure of claim 1 which also includes operating means to actuate said rotary adjustable swivel member to angularly position the bucket during the opera! tion of the machine.

6. A suspension joint for an earth moving machine comprising a clamshell bucket having its halves hinged together, a link pivoted to each corner of said bucket and in spaced relation to the hinge between said bucket halves, a horizontal bearing plate, a plurality of spaced parallel gusset plates depending from the underside of said bearing plate on opposite sides of the center thereof, quadrangularly arranged spaced pivot means on said gusset plates to receive the other ends of said links, a second bearing plate mounted for rotation about a vertical central axis on the first bearing plate, and lock means connecting both of said bearing plates to prevent relative rotary motion therebetween, universal joint means on said second plate to suspend said bucket vertically.

7. The structure of claim 6 which also includes a bucket stick movably mounted on a boom and from which said bucket is suspended by said universal joint means.

References Cited in the file of this patent UNITED STATES PATENTS Osgood May 16, Fogarty June 12, Carroll Dec. 9, Robinson Aug. 11, Baker Oct. 19, Billings Feb. 11, Evelev J an. 14, Billings July 26, Browning Aug. 5, Glashaw May 19, Johnson Sept. 8, Troyer Oct. 20, 

